The present invention relates to sewing machine speed control systems, and in particular to a digital sewing machine speed control system in which the operating condition of the machine is controlled in response to a command signal derived from a plurality of binary digits indicating the position of a foot pedal.
Conventional sewing machine speed control systems include a circuit that generates a speed setting signal in response to the amount of depression of an operator-controlled foot pedal. The speed setting signal is typically generated by a magnetic sensor located with respect to a permanent magnet which is mounted for movement with the foot pedal, whereby the depression of the pedal results in a variation in the output of the magnetic sensor.
However, the conventional systems are not satisfactory in that the pedal stroke versus speed characteristic of the machine for various sewing operations is not optimized from the standpoint of human engineering. Furthermore, the conventional systems are not readily adapted for application to microcomputer technology.